Liquid pumping mechanism



July 10, 1934.

w. F. TRAUDT LIQUID PUMPING MECHANISM 2 Sh eets-Sheet 1 .Filed Aug. 6.1950 N Filed Aug. 6, .1930 2 Sheets-Sheet 2 j fzyrma fi/M 4% kw,

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Patented July I0, 1934 LIQUID PUMPING MECHANISM William F. Traudt,Buffalo, N. Y.

Application August 6, 1930, Serial No. 473,35?

Claims.

This inventionrelates to pumping mechanisms or systems for handlingliquids such, for instance, as acids or other chemicals, the leakage orescape of which would result in danger or annoyance 5. or entailobjectional loss.

One usual arrangement heretofore employed for handling such liquidscomprises a centrifugal pump located on the floor or .ground outside ofthe liquid storage tank andconnected by a suitable suction pipe to thetank. In such an arrangement the stufiing box of the pump shaft issubjected to the static pressure within the liquid tank, and the leakageof the liquid through the standing box is practically inevitable..Another known arrangement is to mount a horizontal centrifugal pump,together with a primer for the pump on top of the storagetank or abovethe liquid level therein, but this arrangement also is objectionablesince the stuffing box is subject to the static pressure of the liquidWithin the priming chamber and leakage can occur through the stufiingbox.

Among the objects of my invention are the following: to provide apumping mechanism in which leakage of the pumped liquid through the pumpstuffing box is efiectually prevented; also to provide a pumpingmechanism which includes a priming device for the pumpand in which thestufiing box of the pump is arranged so as to prevent leakage of theliquid; also to provide a centrifugal pumping mechanism embodyi g anovel relationship of the pump stuifing box to the pump priming chamberwhereby leakage of the liquid is prevented; and also to provide apumping mechanism for liquids which embodies the other features ofadvantage and improvement hereinafter described and set forth in theclaims.

In the accompanying drawings:

Fig. 1 is an elevation, on a reduced scale, of a liquid storage tankhaving mounted thereon a pumping mechanism embodying my invention.

Fig. 2 is an elevation, partly in section, of the pumping mechanism.

Fig. 3 is a sectional elevation, on an enlarged scale, of the stuffingbox for the pump.

Fig. 4 is an elevation, partly in section, of a modified constructionembodying the invention.

Referring first to the construction shown in Figs. 1 to 3, 10 representsa liquid storage tank which may be a container or reservoir of anysuitable sort for the liquid to be pumped. 11 indicates the pump and 12a priming chamber for the pump. The pump may be of known construction,but it is arranged vertically or with its rotary drive shaft 13extending upwardly from the pump, and it may be driven by any suitablemeans, such for example as an electric motor. 14. mounted above the pumpand connected to the upper end of the pump shaft 13. In the constructionshown the pump 11, which is a centrifugal pump, and the priming chamber12, are mounted side by side on a suitable base 15 which is stationarilysecured on top of the liquid storage tank. The suction intake pipe 16 ofthe pump connects with the lower end or portion of the priming chamber12, and a suction line connects the priming chamber with the liquidstorage tank, the suction line communicating at its lower end with thetank at the bottom of the latter, and communicating at its upper endwith the priming chamber at an elevation above that at which the primingchamber communicates with the pump intake 16. This suction line, asshown, is formed by a bottom suction connection 17 on the primingchamber, a pipe 18 detachably coupled to said connection and extendingtherefrom down into the storage tank, and a pipe 19, which is arrangedvertically within the priming chamber, is connected at its lower end bya screw or other suitable joint with the suction connection 17, andopens at its upper end into the upper portion of the priming chamber.The upper end of the priming chamber is closed preferably by a removablecover 20 which may be tightly secured in closed position, as by a clamp21. The pump discharge pipe or line 22 extends from the pump to a higherlevel.

Before the pump is first started for drawing liquid from the storagetank, the priming chamber 12 is filled with the liquid, preferably up tothe level of the top of the suction pipe 19, which can be done byremoving the cover 20 or inany other suitable way. The intake 16 of thepump being connected to the bottom or lower portion of the primingchamber 12, the pump will be primed by the liquid from the primingchamber, and when the pump is started, it will draw the liquid from thepriming chamber, lowering the level of the liquid therein. Since thelower end of the suction line is sealed by the liquid in the tank 10, apartial vacuum is thus created in the priming chamber above the liquid,and this, if the suction line is air bound, will draw the air from thesuction line and cause the liquid to rise in the suction line and enterthe priming chamber. The capacity of the pump intake and the primingchamber up to the level of the upper end of the suction pipe should beat least'equal to and preferably somewhat greater, than the capacity ofthe suction line from its lower to its upper end, so that the liquidwill rise through the suction line and enter the priming chamber 12before the priming chamber can be emptied sufficiently to uncover thepump intake and permit air to enter the pump. Thus, after the primingchamber has once been filled and the pump started, the pump can continuein operation and will be kept primed until the storage tank is emptied,or the liquid lowered in the same to the lower end of the suction pipe18. If the pump is stopped before the liquid in the storage tank islowered to the bottom end of the suction pipe 1'7, the liquid willbackwash from the pump discharge pipe 22 through the pump and pumpintake 16 into the priming chamber 12, and if the volume of liquid inthe discharge pipe is more than enough to fill the priming chamber 12 upto the level of the upper end of the suction pipe 19, the liquid willenter the suction pipe 19 and flow back into the storage tank. Liquid isthus always kept in the ,priming chamber and the pump is kept primed, sothat it can be again started to withdraw more liquid from the storagetank, and this action can be repeated until the tank is emptied.

According to my invention, the casing of the centrifugal pump isprovided with an extension or sleeve which projects upwardly around thepump shaft 13 and is provided at its upper end with a stufiin'g boxthrough which the pump shaft extends. This casing extension, in theconstruction shown, is formed by a tube 23 secured at its lower end by aliquid-tight joint to the pump casing proper, and a stuffing box orhollow casting 24 which is secured by a liquid-tight joint to the upperend of the tube 23. The stuffi-ng box may be of usual constructionhaving an adjustable gland 25 and screw cap 26 at its upper end forcompressing suitable shaft packi-ng 2'7 surrounding the pump shaftwithin the stuffing box. The upper or outer end of the stufbox, whichconstitutes a part of the upward extension of the pump casing, islocated at a level above the upper end of the suction pipe 19 in thepriming chamber, and therefore at a level above the highest level towhich the liquid can rise in the priming chamber. Because of thislocation of the stufiing box relatively to the priming chamber, therecan be no leakage of the liquid out through the stufling box and theloss of the liquid or danger or annoyance from leakage of the same isprevented.

The pump may advantageously be of the type, well known in the art, whichproduces a suction at both faces of the shroud, so that suction will becreated around the impeller shaft where the shaft enters the pumpingchamber. Pumps of this type are disclosed, by way of example, in thepatents to Jackson, 440,252 of November 11, 1-890, and 'Schoene, 768,911of August 30, 1904.

Preferably the upper end of the stufling box is submerged in a body ofoil or ot er suitable liquid 30 contained in a receptacle 31 into whichthe upper end of the stuffing box projects. This receptacle :31 as shownis mounted on a bracket 32 secured to the upper portion of the primingchamber 12 and forms the support for the frame 33 on which the drivingmotor 14 for the pump and the upper bearing 34 for the pump shaft aremounted. By thus keeping the upper end of the 'stufiingbox submerged inoil, the pump can be operated for pumping liquid from a tank containinga vacuum or under a condition where, due toa high suction lift on thesuction pipe a vacuum might be created -in the pump column 23. The oilwill seal the shaft opening of the stuiiing box and prevent entrance ofair through the same.

The pump mechanism shown and described, comprising the pump and thepriming chamber mounted on the base 15, and the driving motor mounted onthe prirmng chamber, constitutes a unitary structure which can behandled and readily installed as a unit on top of the storage tank andconnected to the suction and discharge pipes.

In the mechanism, as thus far described and as illustrated in Figs. 1 to3, the pump is primed automatically or kept primed, and the mechanismperforms as stated without the necessity for any valves or closuredevices for maintaining the priming body of liquid in the primingchamber or suction line. This simple construction adequately meetsordinary requirements. Certain additional advantages, however, areobtained by the construction shown in Fig. 4.

This latter construction, shown in Fig. 4, is the same as described andillustrated in Figs. 1 to 3, except that the suction line is providedwith a check valve 35, preferably located at the lower end of thesuction pipe 18, and an open air pipe 36, which is preferably of smallsize relatively to the suction line, communicates with the primingchamber 12 above the highest level which the liquid reaches therein, andextends down into the storage tank substantially to its bottom.

Without the check Valve 35 and air pipe 36, when the pump stops, theliquid in the discharge line would backwash into the priming chamber andforce the air therein out through the suction line; thus after thebackwash had been completed, the suction line would remain full of air,particularly if the volume of the discharge line did not equal thevolume of the priming chamber.

But with the check valve 35 in the suction line, the backwash will forcethe air trapped in the priming chamber out through the small pipe 3.6,allowing the liquid to remain in the entire suction line. The smallauxiliary air pipe will not interfere in any way with the properoperation of the pump. The added check valve and small air pipetherefore extend the usefulness of the apparatus as a whole and make itmore flexible.

I claim as my invention:

1. In combination, a pump, a priming chamber communicating with the pumpintake, said parts being constructed so that liquid .can backwashthrough the pump into said priming chamber, a suction pipe communicatingwith said priming chamber at a level above that to which the liquidrises in said priming chamber, means which prevent backflow of liquidfrom said suction pipe, and an air passage extending from the primingchamber at a point above the liquid therein to a point. submerged in thebody of liquid being pumped.

2. In combination, a liquid holding tank, a pump for discharging thesame, a-priming chamber communicating with the pump intake, said partsbeing constructed so that liquid can backwash through the pump into saidprimingchamber, asuction pipe extending from said tank and communicatingwith said priming :chamber at a level above that at which the pumpintake communicates with the priming chamber, a check valve whichprevents discharge of liquid from the suction pipe into the tank, and anair passage extending from the upper portion :of the priming chamber andcommunicating with the lower portion of said tank.

3. A pump unit comprising a base, a :priming tank mounted on said base"and extending upwardly therefrom, a centrifugal pump also mounted onsaid base adjacent the lower part of said tank, said pump having animpeller shaft extending upwardly therefrom to a height above the upperend of said tank; said pump also having a tubular shell extending aroundsaid shaft also to a height above said tank, means connecting the upperend of the shell to the upper end of said tank whereby the upper ends ofsaid shell and tank steady one another, a stufiing box at the upper endof said shell through which said impeller shaft extends, means connectedto the upper end of said shaft for driving it,'a bearing for the upperend of said shaft disposed above said stufling box and connected forsupport to the upper end of said shell, a pipe connecting the lower partof said tank to the suction inlet of said pump, and a riser suction pipeopening into said tank adjacent the upper end thereof, whereby liquidwill be drawn through said suction pipe into and through said tank onits way to said pump, and liquid in said tank will prime said pumpautomatically at the starting of the pump.

4. A pumping mechanism for lifting a liquid from a lower level to ahigher level and comprising a pump located between said levels, apriming tank at a level above said pump and below said higher level, asuction pipe extending from the inlet port of said pump into the liquidto be elevated and including, in series therein, said tank with theconnection from the tank to the pump opening into the lower part of thetank and with the portion of the suction pipe that leads to said tankfrom said liquid, opening into the upper part of said tank, wherebyliquid elevated by said pump will pass through said tank on its way tosaid pump, a delivery pipe leading from said pump to said higher level,whereby back wash in said delivery pipe upon stopping of said pump willcause some filling of said tank to provide a priming supply therein, anautomatic check valve in said suction pipe between said tank and theinlet end of said suction pipe, and a relatively small air pipe openingat one end into the upper part of said tank-and at its other enddepending into the liquid to be elevated, whereby when said pump stops,the suction pipe and said tank will be kept substantially filled.

5. A pumping mechanism for lifting a liquid from a lower level to ahigher level and comprising a pump located between said levels, a prim--ing tank at a level above said pump and below said higher level, asuction pipe extending from the inlet port of said pump into the liquidto be elevated and including, in series therein, said tank, with theconnection from the tank to the pump opening into the lower part of thetank, and with the portion of the suction pipe which leads to said tankfrom said liquid opening into the upper part of said tank, wherebyliquid elevated by said pump will pass through said tank on its way tosaid pump, a delivery pipe leading from said pump to said higher levelwhereby back wash from said delivery pipe upon stopping of the pump willcause some filling of said tank, said pump having a vertically extendingoperating shaft, a sleeve surrounding said shaft and extending from thepump casing to a level above the maximum possible liquid level in saidtank, a stufiing box between 1:00 the upper end of said sleeve and saidshaft, whereby the maximum elevation to which liquid will rise in saidsleeve, when said pump is quiet, will not exceed the maximum possibleupper liquid level in said tank and reach said stufiing box, an 105automatic check valve in said suction pipe between said tank and theinlet end of said suction pipe, and a smaller air vent pipe opening atone end into said tank adjacent the upper end thereof having its highestpoint below said stuffing box, and opening at its other end into saidliquid to be elevated, whereby upon a stopping of the pump the suctionpipe will be kept substantially filled, a supply of priming liquid willbe available in said tank, and the pressure on the liquid in the pump115 tending to cause it to rise in said sleeve will not cause anelevation of liquid in the sleeve above the highest point of said smallair vent pipe.

WILLIAM F. TRAUDT.

